Explanation:
This is what a star really looks like from the surface of the Earth.
To the best the
human eye can see, stars are so far away they appear
the same as would infinitesimal points of light.
The
Earth's atmosphere, however, is clumpy, so that
different air pockets produce different images
of a single point-like star.
Because the atmosphere is always
windy and changing, the number and position of images is always changing,
with the result that stars appear to
twinkle.
In reality, the
above time-lapse sequence occurs ten times faster.
Close inspection will reveal a
single small image of the star that is repeated over and over.
This image is called a
speckle and its size is again not really infinitesimal,
but determined by
strange quantum effects that involve the finite size of the telescope.
Recent work in
adaptive optics ("rubber mirrors") have made
spectacular advances
in reducing this atmospheric blurring.
Betelgeuse is the star twinkling above,
and in space, above the Earth's atmosphere,
it really looks like this.